Boiler



E. LUNDGREN 1,983,624

BOILER Filed April 16, 1932 3 Sheets-Sheer. 1

Rig.- 1.

ENTOJR 1 ATTORNE ec. 11, 1934. E. LUN'DGREN' BOILER Filed April 16, 1932 3 Sheets-Sheet 2 ATTORN Y Patented Dec. 11, 1934 UNITED STATES PATENT OFFICE 1,983,624 BOILER Edwin Lundgren, Frederick, Md., assignor to Foster Wheeler-Corporation, New York, N. Y., a corporation of New York Application Aprii16, 1932, Serial No. 605,617

Claims. (Cl. 122-331) 5 vide a water tube boiler of novel design, adapted particularly for high pressure duty, which is characterized by economy of manufacture, compactness in design and greater efficiency in operation.

This and other objects which will appear from the following description, are attained, in general, by the use of a single steam and water drum and straight headers which are connected directly into the drum by boiler tubes having a relatively long horizontally inclined straight run and a relatively long vertical run. The upper ends of the boiler tubes are swaged directly into the drum thereby eliminating all intermediate headers and connections and providing adequate freedom for expansion of the tubes and freedom of circulation of the steam and water, the latter being of particular importance in high pressure boilers. The boiler tubes exposed to the highest degree of heat are connected to the drum above the water line to reduce the disturbance of the water level and the moisture in the steam leaving the drum. The downcomers are disposed closely adjacent to or in the plane of the roof and a wall of the setting and with the arrangement of boiler tubes as described, adequate space is provided in the setting between the downcomers and boiler tubes for primary and secondary or reheat superheaters. Suitable baffling and damper controls are utilized to direct and control the flow of gases over the boiler and superheater and reheater tubes so that the desired degree of superheat and reheat may be obtained.

The natureof-the invention will become apparent from the following description of preferred forms of the invention when considered in connection with the accompanying drawings forming a part hereof, and in which:

Fig. 1 is a longitudinal sectional view of a high pressure water tube boiler constructed in accordance with the present invention;

Fig. 2 is a fragmentary sectional view taken substantially on line 2-2 of Fig. 1;

Fig. 3 is an enlarged fragmentary sectional view showing the manner in which the boiler tubes are connected to the steam and water Fig. 4 is an enlarged elevational view of a section of a form of damper that may be utilized;

Fig. 5 is a fragmentary longitudinal sectional view of the damper; and

Figs. 6 and 'l are fragmentary longitudinal sectional views, similar to Fig. 1, showing different arrangements of the flue and economizer. Like.characters of reference refer to like parts throughout the several views.

Referring to the drawings, reference character 10 indicates, in general a boiler setting comprising a front wall 11, a rear wall 12, side walls 13 and 14 and a roof 15. A combustion chamber 16 is located in the lower part of the setting.

In accordance with this invention, a single transverse cylindrical steam and water drum 17 is suitably supported in the uppermost part of the setting adjacent and parallel to the front wallll. A plurality of downcomers 18 are suit-' ably connected at their upper ends to the lower portion of the drum 17 and at their lower ends are connected to straight headers 19 suitably supported in a. vertical position in the setting. As shown, these downcomers extend radially from the drum 17 and are bent or curved in the form of an L, substantially, with their upper legs extending horizontally or approximately so, along or adjacent to the roof of the setting and with their lower legs extending vertically in the-plane of the back wall 12 of the setting. The upper horizontal legs of the downcomers are arranged in two rows, with alternate legs lying in an upper row extending along the roof 15 and with the remaining legs lying in a lower row somewhat below the upper row. As shown the legs of the downcomers in the lower row are suitably bent for convenience in connecting the downcomers to the drum. With this arrangement, the connections of the downcomers with the drum are staggered. 1

A plurality of boiler tubes 20 extend from each of the vertical headers 19 directly into the drum 17. These tubes are also curved or bent to form an L, substantially, with their lower legs extending in a horizontally inclined direction from the headers in the rear wall to points adjacent the front wall of the boiler where they are bent upwardly to provide vertical legs which extend from the bends to suitable points adjacent the drum 17 where they are again bent so that the tubes will all extend in a radial direction into the drum. At their extreme upper or drum ends, the tubes 20 are somewhat reduced in diameter as shown, and are secured to the drum shell by swaging as indicated at 21 in Fig. 3. The use 'of the swaged connection of the tubes with the drum provides for a greater ligament efliciency of the drum shell and permits the use of a thinner drum for the same steam pressure than with other forms of connections heretofore used. The use of the L-shaped boiler tubes 20 with their relatively long horizontally inclined and their relatively long vertical runs and with their direct connection into the drum without intermediate headers, drums or connections permits great freedom for expansion of the tubes and further provides substantially constant cross-sectional flow areas or complete unrestricted circulation which becomes of prime importance as steam pressures are increased. The horizontally extending leg of the innermost of the tubes is preferably spaced a greater distance than normal from the adjacent legs as shown to equalize the flow of the products of combustion over the tubes.

Because of the shape and arrangement of the tubes as described, ample space is provided between the downcomers and the boiler tubes for the relatively large primary and secondary or reheat sup-erheaters normally required with high pressure steam installations. Referring particularly to Fig. 1, the primary superheater is mount ed directly above the horizontally inclined legs of the boiler tubes 20 and the reheat superheater is mounted directly above the primary superheater. The primary superheater consists of cylindrical inlet and outlet headers 22 and 23 respectively, suitably supported on the boiler setting, and which are connected by a plurality of U-shaped elements or loops 24 supported by beams 25 mounted in the setting. A steam pipe 80 connects the upper part of the steam and water drum with inlet header 22 of the primary superheater. The reheat superheater consists of cylindrical inlet and outlet headers 26 and 27 respectively connected by a plurality of U-shaped elements or loops 28 supported from the setting by beams 29. Doors 30 and 31 are provided in the setting through which the superheaters may be removed.

Suitable bafiling is provided to direct and control'the flow of the products of combustion over the boiler and superheater tubes. As shown, a horizontally inclined baflie member 32 extends along the horizontally inclined legs of the innermost of the tubes 20 from side to side of the boiler setting and from the headers 19 to a point short of the vertically extending legs of the tubes 20. A baflie 33 extends along the lower legs of the lowermost of the elements 24 of the primary superheater. This baffle also extends from side to side of the boiler but terminates short of both ,the back wall 12 of the boiler and the vertical legs of the boiler tubes 20. A baiile 34 extends along the upper legs of the uppermost of the elements 24 of the primary superheater and reaches the entire width of the boiler and extends from the front wall 11 of the boiler where it contacts with a short baflle 35 toward the back wall 12 but terminates short thereof. A bafile 36 similar to baffle 33 is supported on the lower legs of the lowermost elements 28 of the reheat superheater and a baffle 37 similar to bathe 32 extends along the upper legs of the uppermost of the elements 28 of the reheat superheaters. The space 38 between bafiles 32 and 33 and the space 39 between baffles 34 and 36 provide by-passes for the products of combustion in their course from the furnace to the flue. These paths 38 and 39 are each controlled by a damper 40. As better shown in Figs. 4 and 5, these dampers extend entirely across the boiler setting and consist of a plurality of damper sections or units 41 of suitable refractory construction as possible.

of a substantially square central portion 43 with I substantially triangular portions 44 extending from two opposite sides of the central portion. The triangular portions 44 are preferably hollowed out as shown at 45 to provide as light a The shafts 42 are mounted in suitable bearings at the'sides of the boiler. One of these bearings is indicated at 46 in Fig. 5. The shafts are connected by conduits 47 with a source of water supply to cool the shafts. The dampers may be operated by any suitable means. As shown, a pulley 48 is fixed to the shaft at one end and is operated by a belt 49 running over a suitable operating device not shown. It is apparent that many other forms of dampers and damper shafts may be utilized if desired without departing from the invention. With this arrangement of baiiles and dampers, it will be clear that the volume of gases passing over the primary and reheat superheaters may be readily controlled to provide the desired degree of superheat and reheat.

As shown in Fig. 1, the products of combustion are removed from the back of the boiler through a flue 50 and flow upwardly over an economizer above the economizer so that the gases will pass first over the economizer and then over the air heater. When the gases are so removed that they come in contact with or flow over the downcomers 18, the latter are provided with suitable insulation 52 to assure a maximum amount of steam free water reaching the headers 19 and to provide against these downcomers acting as heat recovering surfaces The insulation 52, which preferably surrounds the horizontally extending and the upper portion 01' the vertically extending legs of the downcomers, is terminated at the upper legs of the uppermost loop 28 of the reheat superheater. The lower portions of the vertically extending legs of the downcomers from the top of the reheat superheater to the headers 19 are insulated preferably by means of insulating blocks 53 disclosed in my copending application Serial No. 595,570 filed February 27, 1932. If desired, the flue may be arranged for a downward flow of the gases immediately upon leaving the boiler.

Fig. 6 shows a boiler constructed in accordance with the present invention with a different arrangement of superheater and reheater headers, flue and by-pass dampers than that shown in Fig. 1. The inlet and outlet headers and 61 respectively of the primary superheater and the inlet and outlet headers 62 and 63 respectively of the secondary or reheat superheater are arranged side by side instead of one above the other as in Fig. 1. The dampers 40 are both disposed at the rear of the boiler, that is to say, the damper for the by-pass 38 is disposed at the outlet rather than at the inlet end of the by-pass and the damper for the by-pass 39 is located at the inlet end of the'by-pass. The gases are removed from the boiler near the central portion of the roof through a flue 64 and flow over an economizer 65 and/or an air heater arranged in the flue. The downcomers 18 with this arrangement are also provided with suitable insulation to provide a maximum amount of steam free water at the headers 19 and to prevent the downcomers from acting as heat recovering surfaces.

The arrangement shown in Fig. 7 is substantially the same as that shown in Fig. 1 with the exception that the products of combustion are removed at the front end of the roof of the boiler through a flue 70 having an eoonomizer '71 disposed therein." The gases after flowing over the economizer are drawn through a conduit 72 by an induced draft fan 73 after which they are delivered to the stack '74. Inasmuch as in this arrangement, the gases do not come in contact with nor flow over the horizontal legs nor the upper portions of the vertical legs of the downcomers 18, it is unnecessary that they be insulated. The lower portion of the vertical legs of the downcomers are insulated however with insulating blocks 53 as described in connection with Fig. 1.

As clearly indicated in Fig. 2, the boiler tubes- 20 are disposed in alignment in vertical rows, each row of tubes being so spaced that the lanes 90 defined by the tubes are of ample width to permit the removal from the boiler of any tube through one of the lanes. Accordingly tube removals may be effected simply by cutting the desired tube or tubes at the header and steam drum ends, moving the tube to an' adjacent lane 90 and withdrawing it through the lane and out of the boiler.

Thus is provided a boiler particularly well adapted for high pressure duty, which is extremely compact, of low cost and efficient in operation. It is well known that the drums in high pressure boilers constitute the largest item of expense. In accordance with the present invention, only a single steam and water drum is necessary, thus providing for low first cost and maintenance. Moreover the direct connection of the tubes to the drum by swaging results in a high ligament efliciency of the drum and permits the use of a somewhat lighter drum for any given steam pressure which is also conducive to a low first cost. In addition, the connection of those boiler tubes which are exposed to the highest degree of heat, to the steam and water drum at points above the water line in the drum reduces the disturbance of the water level and the moisture in the steam leaving the drum. Further, with the arrangement and disposition of the downcomers and boiler tubes and the direct connection of the latter into the drum without the use of intermediate headers or connections, a compact and efiicient unit of boiler and primary and reheat superheaters is possible together with freedom'for expansion of the tubes and unrestricted flow of steam through the tubes into the drum.

Since it is apparent that many changes may be made in the form, arrangement and combination of parts herein disclosed without departing from the spirit or scope of the invention, it is understood that no intention is entertained to limit the invention except by the scope of the appended claims.

What I claim is:

1. A boiler comprising a setting having opposed walls and a roof, a furnace in the setting, a steam and water drum in the upper part of the setting, a plurality of headers arranged substantially in the plane of one of the walls of the setting, downcomers connecting the drum and headers and having portions extending adjacent and parallel to the roof and other portions lying substantially in the plane of the last mentioned wall, a plurality of boiler tubes connecting the headers directly with the drum, the boiler tubes having portions extending in a horizontally inclined direction and other portions extending in a substantially vertical direction adjacent the wall opposite said last mentioned wall of the setting, a superheater in the setting in the space defined by and between the downcomers and boiler tubes, a first and second bafile disposed respectively above and below the greater part of said superheater, the space between said bafiles defining a passage for the products of combustion over said superheater, a third bailie disposed below said second baiiie and above the horizontally inclined portion of the boiler tubes and spaced from said second baffle to provide a by-pass for the products of combustion passing through the setting without coming in contact with the superheater, and a damper controlling the by-pass to thereby control the quantity of products of combustion flowing over the superheater.

2. A boiler comprising a setting having opposed walls and a roof, a furnace in the setting, a steam and water drum in the upper part of the setting, a plurality of headers arranged substantially in the planeof one of the walls of the setting, downcomers connecting the drum and headers and having portions extending adjacent and parallel to the roof andother portions lying substantially in the plane of the last mentioned wall, a plurality of boiler tubes connecting the headers directly with the drum, the boiler tubes having portions extending in a horizontally inclined direction and other portions extending in a substantially vertical direction adjacent the wall opposite said last mentioned wall of the setting, a superheater in the setting in the space defined by and between the downcomers and boiler tubes, a first and second baflle disposed respectively above and below the greater part of said superheater, the space between said baffles defining a passage for the products of combustion over said superheater, a third baffle disposed below said second bafiie and above the horizontally inclined portion of the boiler tubes and spaced from said second bailie to provide a by-pass for the products of combustion passing through the setting without coming in contact with the superheater, a damper controlling the by-pass to thereby control the quantity of products of combustion flowing over the superheater, a reheater in the setting disposed above the superheater, a fourth and fifth bafiie disposed respectively above and below a greater part of the reheater, the space between said fourth and fifth baflies providing a path of flow of the products of combustion over the reheater, said fifth bafile being spaced from said first battle to provide a by-pass for the products of combustion passing through the setting without coming in contact with the reheater, and a damper controlling said reheater by-pass to thereby control the quantity of products of combustion flowing over the reheater.

3. A boiler comprising a setting having opposed walls, a steam and water drum in the upper part of the setting, a plurality of headers in the setting, downcomers connecting the drum and headers and having substantially horizontally and vertically extending portions, a plurality of boiler tubes connecting the headers directly with the drum, the boiler tubes having portions extending in a horizontally inclined direction and other portions extending in a substantially vertical direction, a superheater in the setting in the space defined by and between the downcomers and boiler tubes, a first and second baffle disposed respectively above and below the greater part of said superheater, the space between said bafiies defining a passage for the products of combustion over said superheater, a third baifie disposed below said second baflle and above the horizontally inclined portion of the boiler tubes and spaced from said second bafile to provide a by-pass for the products of combustion passing through the setting without coming in contact with the superheater, and a damper controlling the by-pass to thereby control the quantity of products of combustion flowing over the superheater.

4. A boiler comprising a setting having opposed walls, a steam and water drum in the upper part of the setting, a plurality of headers in the setting, downcomers connecting the drum and the headers and having substantially horizontally and vertically extending portions, a plurality of boiler tubes connecting the headers directly with the drum, the boiler tubes having portions extending in a horizontally inclined direction and other portions extending in a substantially vertical direction, a superheater in the setting in the space defined by and between the downcomers and boiler tubes, a first and second bafile disposed respectively above and below the greater part of said superheater, the space between said baflies defining a passage for the products of combustion over said superheater, a third baffle disposed below said second bafiie and above the horizontally inclined portion of the boiler tubes and spaced from said second baflie to provide a by-pass for the products of combustion passing through the setting without coming in contact with the superheater, a damper controlling the by-pass to thereby control the quantity of products of combustion flowing over the superheater, a reheater in the setting disposed above the superheater, a fourth and fifth balile disposed respectively above and below a greater part of the reheater, the space between said fourth and fifth baffles providing a path of flow of the products of combustion over the reheater, said fifth baflie being spaced from said first bafile to provide a by-pass for the products of combustion passing through the setting without coming in contact with the reheater, and a damper controlling said reheater by-pass to thereby control the quantity of products of combustion flowing over the reheater.

5. A boiler comprising a setting, a steam and water drum in the upper part of the setting, a circulatory system including downcomers and boiler tubes connected with the drum, the downcomers and boiler tubes being arranged in the setting so as to provide a space between them suflicient to accommodate a steam heater, the boiler tubes having a portion extending in a horizontally inclined direction and another portion extending in a substantially vertical direction, a steam heater in said space, spaced baflles disposed with respect to the steam heater so as to provide a path for the flow of products of combustion over the heater, another baflie spaced from said baflies and providing a by-pass for the products of combustion around said heater, and means controlling the flow of products of combustion through the by-pass to thereby control the quantity of products 01 combustion flowing over the heater.

EDWIN LUNDGREN. 

